Cocotb test suite

[javathunderman]

Figure out why the four bit counter example synthesized using Calyx was not running properly with the cocotb unit tests; start writing tests for map/reduce function primitive

[javathunderman]

OK this was a fairly obvious oversight on my end, the read_data port only becomes active with the value that is being read - it does not represent the memory state. Need to find some other way of determining that post-simulation

[javathunderman]

Added a rule for this into the Makefile in e8f3a70, maybe that could be a basis for writing more standard unit tests (diff'ing the JSON output, use cocotb for cycle-level correctness checks?)

[javathunderman]

todo: make sure that we can show scalability (focus on parscan?) as part of the evaluation